Pixie, I'm afraid you're right, I need to re-do the tectonics, hopefully second time around they can also explain at least a few mountain ranges so they can be very high and sharp, not so small and eroded. I'll try to apply your suggestions as best as I can. Also, you made me think about those big islands and yes... I think too their too big to be volcanic islands.

Ilanthar, I agree my "mountains" are a bummer, but after all, the colors/terrain of the current map are supposed to be just a ready visual guide for when I try to do the final terrain with Tear's tutorial, because I'm terrible at drawing/painting and such, I have no vision for it, so I can't just improvise, I need to have a template before I work on the tutorial to do the real terrain.

I'm not surprised I messed up with the rivers too, but for now I'll forget about them since first I've got to fix the tectonics and the climate issues. I read a bit about giving the planet a different tilt, but the consequences are too extreme and don't quite fit my story, so I'm still thinking what to do about it.

Anyway, thanks you two too for your comments.